#斐波拉契数列
def Fib(n):
    if n == 1 or n == 2:
        return 1
    else:
        return Fib(n-1)+Fib(n-2)
if __name__ == '__main__':
    print(Fib(int(input("请输入一个数字："))))
    print(Fib(5))